This invention relates to fuel control systems, particularly to fuel injection systems for 2-cycle, internal combustion engines.
Waves and water level fluctuations cause the load on the propulsion system of a boat to vary. This variation may be significant when the boat is trolling or even while the boat is idling. This in turn causes the engine speed to rise in fall. This variation in engine speed causes irregular combustion, fuel wastage, and may cause the engine to stall.
Japanese Unexamined Patent Publication Heil-294936 discloses a fuel injection control system for the 2-cycle engine in which air is supplied to the combustion chamber through an intake passage while fuel is injected directly into the combustion chamber mixed with air.
As the engine load is varied by waves or water level fluctuations while the boat is running with the throttle opening kept fixed, the engine revolution speed also varies and the passengers may feel unpleasant. To stabilize the engine revolution speed of a crank case scavenged, two stroke engine, prior fuel injection control systems have adjusted the intake air amount by adjusting the throttle opening, and the intake passage cross-sectional area.
However, this requires the installation of actuators for adjusting the throttle opening, and the intake passage cross-sectional area, to stabilize the engine revolution speed by adjusting the intake air amount. The performance of these systems may deteriorate over time due to salt damage to the actuators.
Thus there was felt a need for an engine speed regulating system which would effectively reduce engine speed variation without requiring the installation of additional actuators.